Field of the Invention
The present invention relates to a clamper that clamps a plate-shaped workpiece when the workpiece is immersed in a surface treatment liquid such as a plating solution, and surface treatment such as plating is performed, and also to a holding jig including the clamper.
Description of the Related Art
Holding jigs (baskets) capable of holding plate-shaped workpieces, such as printed circuit boards and glass substrates, that are equidistantly arranged, are known. For example, in the basket disclosed in Japanese Patent No. 4,914,780, a workpiece holding space is formed by a support frame in the form of a rectangular parallelepiped. Side holding portions for holding workpieces are provided on the mutually opposing beam sections among the beam sections installed between the pillars of the support frame. The side holding portions are arranged equidistantly at the beam sections. A large number of workpieces can be equidistantly held by inserting the side portions (edges) of the workpieces between the side holding portions from above.
Further, Japanese Patent No. 3,348,092 and Japanese Utility Model Registration No. 3,153,550 disclose a holding jig that can hold thin flexible workpieces in a spread state. More specifically, the holding jig shown in FIGS. 1(a) and 1(b) of Japanese Patent No. 3,348,092 is provided with a conductive extension member biasing an auxiliary frame portion in the extension direction of the workpieces. The holding jig shown in FIG. 6 of Japanese Utility Model Registration No. 3,153,550 has a structure in which the lower end portion of a workpiece is pulled downward with biasing means.
Further, Japanese Utility Model Registration No. 3,153,551 and Japanese Utility Model Application Publication No. H5-74677 disclose a holding jig provided with a clamper that clamps a workpiece. More specifically, the clamper shown in FIGS. 3 and 4 of Japanese Utility Model Registration No. 3,153,551 is provided with a first clamper lever having a first clamping surface and a second clamper lever having a second clamping surface, and where a workpiece is clamped, the first clamping surface and the second clamping surface are brought into contact with the workpiece. The clamper shown in FIGS. 1(A) and 1(B) of Japanese Utility Model Application Publication No. H5-74677 is provided with a bent member in which clamping portions are curved surfaces.
With the conventional techniques, when the holding jig (basket) holding workpieces is immersed into a plating solution or pulled out therefrom, or under the effect of a liquid flow occurring during the immersion into the plating solution, the clamping positions of the workpieces can be shifted and the workpieces can be bent, and in some cases, the workpieces can be detached from the clampers. In such cases, the workpieces can be damaged or plating defects can occur.